The Association Between Variability in Electrolytes and the In-Hospital Mortality in Critically Ill Children in Pediatric Intensive Care Units.

Jilei Lin,Anchao Song,Jihong Dai,Xingping Tao,Meng Chen,Jianchuan Chen,Yin Zhang

doi:10.3389/fped.2021.692894

Abstract

Objective: This study aimed to explore the association between the variability in electrolytes and the in-hospital mortality in critically ill children admitted into intensive care units (ICUs).Design: This is a retrospective case–control study.Setting and Participants: Total of 11,245 children have been admitted to ICUs of Children's Hospital of Zhejiang University from 2010 to 2018.Methods: The coefficient of variation (CV), standard deviation (SD), and variability independent of the mean (VIM) were calculated as variability indices. High variability was defined as having values in the highest quartile for each parameter. Age, sex, diagnoses of disease, and surgical treatment were adjusted in the multivariable-adjusted logistic regression model.Results: A total of 11,245 children were included, and 660 patients died in the hospital. The median (P25, P75) potassium, sodium, and chloride of all patients were 3.8 (3.58, 4.09), 136.83 (135.11, 138.60), and 108.67 (105.71, 111.17), respectively. U-shaped relationships between the mean, lowest, and highest levels of potassium, sodium, and chloride and the in-hospital mortality were observed. The lowest mortality was noted when serum potassium, sodium, and chloride were between ~3.5 and 5.0, 135 and 145, and 105 and 115 mmol/l, respectively. The areas under the curve (AUCs) of three indices of variability in electrolytes were larger than those of the mean and lowest levels of electrolytes in predicting the in-hospital mortality. In the multivariable-adjusted model, the odds ratios and 95% confidence interval (CI) of the in-hospital mortality were 3.14 (2.44–4.04) for one parameter, 5.85 (4.54–7.53) for two parameters, and 10.32 (7.81–13.64) for three parameters compared with subjects having no parameters of high variability measured as the CV. The results were consistent when the variability was determined using the SD and VIM (all P for trend <0.001). Consistent results were noted in various subgroup analyses.Conclusions: This study showed that individuals with higher variability of each parameter were related with higher risk of in-hospital mortality. There was a linear association between the number of high variability parameters and the in-hospital mortality. The variability of electrolytes might be a good predictor for in-hospital mortality of children in ICUs.

Highlights

An adequate electrolyte balance is of paramount importance to maintaining physiologic homeostasis and normal metabolism of cells in human body
This study showed a U-shaped association between the level of serum potassium, sodium, and chloride and the in-hospital mortality of children in intensive care units (ICUs)
The result of receiver operating characteristic (ROC) showed that the variability was more sensitive and stable than the mean, lowest, and highest level of these parameters as risk factors of the in-hospital mortality in critically ill children admitted in ICUs

Summary

Introduction

An adequate electrolyte balance is of paramount importance to maintaining physiologic homeostasis and normal metabolism of cells in human body. Blood gas analysis is conducted regularly and frequently in critically ill patients in ICUs to monitor patients’ physiologic homeostasis. The main items of electrolytes in blood gas analysis are potassium, sodium, and chloride in ICUs. Sodium (Na+) and chloride (Cl−) are the major extracellular ions, while potassium (K+) is the major intracellular cation in the body, and they serve essential functions in the membrane potential and metabolism. It is inappropriate to evaluate the association between serum electrolytes and mortality at a screening visit or using the mean values for pediatric patients with critical illness during the hospitalization, since the serum levels of electrolytes may vary and the normal range of the values is wide in children with different ages. The value of electrolytes may change a lot by the treatment during the hospitalization, so it is inappropriate to use an extreme value to predict the mortality of critically ill children. It is important to choose a better way to fit the relationship between electrolytes and inhospital mortality in critically ill children, which can reduce the influence of baseline and extreme values

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Discussion

Conclusion